Dr Kerry Sherman
Dr Kerry Sherman - Interpreting genetic risk information
In 2009, Dr Kerry Sherman and three international colleagues* published a paper on interpreting genetic risk information in the American Psychology Association’s Health Psychology.
The researchers had recruited a group of 752 adults in Australia, New Zealand and the United Kingdom for an online study. Participants - staff and students at three universities - were randomly presented with a scenario and asked to imagine they were faced with the hypothetical situation. Only the degree of genetic risk and the disease varied in each scenario. The genetic risk was for one of four diseases (diabetes, heart disease, colon cancer and lung cancer) and varied across conditions by 10% increments, from 20% to 100%.
The results revealed two increment clusters in risk likelihood perception: a “moderate-risk” cluster (20%–70%), and a “high-risk” cluster (80%–100%). While all risk increments influenced anticipated worry, feelings of risk, testing-induced distress, and family obligations, the 50% increment attracted responses indicating disproportionately high levels of risk and consequences. This “50 blip” has been previously observed and may have a unique psychological meaning related to the use of terms such as “50-50” to describe uncertain events, creating biased responses.
The study also highlighted national attitudinal differences to genetic testing. Australian and New Zealand respondents perceived the tests as more beneficial than their UK counterparts; New Zealand participants reported greater concerns about insurance and employment discrimination, followed by UK then Australian respondents. Beliefs regarding family obligations for being tested were stronger for New Zealand respondents followed by Australia then the United Kingdom.
In August this year, Dr Sherman and four co-authors** led by Dr Linda Cameron will present their most recent research into public perceptions of genetic testing to the International Congress of Behavioural Medicine conference in Washington.
This time the research compares the impact of genetic versus non-genetic information at varying risk levels and contrasts graphics against numeric formats. Again the study was internet based and involved almost 750 adults responding to a test about colorectal cancer risk. The research explores the comprehension and adaptive behaviour following genetic tests versus tests with a non-genetic biomarker which reveals an enzyme deficiency.
“Genetic tests vary in their prediction of disease occurrence, with some mutations conferring relatively low risk and others indicating near certainty,” said Dr Sherman, a senior lecturer in psychology in Macquarie’s Faculty of Human Sciences***.
“Our earlier study found individuals showed weak sensitivity in their responses to the degree of risk indicated by mutations. Now we are looking at ways to enhance sensitivity to genetic risk, such as by providing risk-action link information that should enhance the understanding of the link between the genetic fault and disease risk, and through the use of graphic representations rather than numerical presentations of disease risk.”
The earlier work, said Dr Sherman, simulated the real-world experiences of consumers receiving minimal information about genetic tests through advertisements and internet sites.
“The research findings contribute to the knowledge base of consumer preferences for genetic tests and may inform funding policies and the provision of counselling and healthcare services. With the growing availability of genetic tests for a multitude of diseases, it is imperative to develop the informational materials, services and policies to meet the psychosocial, economic, and ethical demands created by these procedures,” she said.
Dr Sherman’s research broadly encompasses a social-cognitive view of coping with illness and the threat of illness. She is also the lead investigator of a team awarded a three-year NH&MRC and Cancer Australia grant of $283,000 to evaluate a computer-based aid in decision making regarding breast reconstruction after mastectomy. Dr Sherman has recently completed research into another aspect of breast cancer which focuses on women’s understanding of lymphoedema risk following treatment for cancer.
* Dr Linda Cameron (University of Auckland), Dr Theresa Marteau (King’s College London), Dr Paul Brown (University of Auckland)
** Dr Linda Cameron (University of North Carolina at Chapel Hill), Dr Theresa Marteau (King’s College London), Dr Paul Brown (University of North Carolina at Chapel Hill), Dr William Klein (National Cancer Institute, US)
*** Dr Sherman is also a consultant researcher with the Westmead Breast Cancer Institute, Westmead Hospital, Sydney